According to reports from OpenSecrets.org, in 2006, 151 members of Congress had $195.5 million invested in defense corporations. Their average net worth was $910,000 compared to $100,000 for American families in general. Over 50 range between $5 million and $190 million. John Kerry is at the top end of the scale.
While insider trading carries hefty prison terms for common people, it is perfectly legal for US congressmen. They are free to own shares in companies that are regulated by committees they sit on.
Members of congress can trade freely using insider knowledge they have about regulations or events that could affect specific industries or the stock market as a whole, such as an economic crash, a new law... or a war.
If you are a member of Congress and you sit on a 'defense committee', you are free to trade as much defense stock as you want to. A shocking example is former presidential candidate John Kerry, who has $30 million invested in defense contractors.
Wars are planned by groups such as the Council of Foreign Relations, founded by David Rockefeller. They feature both politicians and CEO's of defense contractors.